scoring chipboard

Chipboard
Yes if you mean a crease to allow folding use matrix or skiv your own with 2 sided tape and cardstock. Very often folding can be acheived with a cut score that cuts part way through the stock and is less of a die load than crease and matrix.
Mike

Akluna- yes, it’s fairly easy: set a piece of scoring rule up in your chase where you need it to score, and then adjust the tympan and/or impression to get the score you want. 20 mils is not that big a deal.

Hi akluna,

Yes, it’s possible. Scoring matrix (Channel creasing matrix) is made by several manufacturers in a range of channel widths to accomodate stocks of different thicknesses. I calculate the width I need by adding the thickness of the two point rule (about .028”) to twice the thickness of the stock (.040” in your case). This would give .068”. Unfortunately, the matrix we use is specified in millimeters, so conversion is necessary. One mm = .03937 inch; .068 divided by .03937 would indicate a channel about 1.7mm wide. The various matrixes (sp?) are distinguished by color: 1.7mm is purple in the brand we use. (Somebody please check my math here. Also the whole method of adding the rule thickness to 2X stock thickness may be a little homegrown. If somebody has better “printing science”, please respond.)

We ordinarily use .900 rule on the Heidelberg platens, and score on the die-cutting jacket, which is .030” without packing. We get our position with a perforating rule, and then replace it with the score rule and matrix.

Chipboard is not a strong stock, and you may have trouble with it breaking a little.

Good luck, Brian

“Somebody please check my math here…”

Your math is good, Brian. 2pt rule=.028” plus twice the thickness of the .020 stock = .068” channel. But rounding up the value of inch/millimeter conversion to .040”/mm is easier. Divide the 68 by two = 34, and then two again, giving 17. Since you know it’s not seventeen millimeters, or .17 millimeter, it must be 1.7mm! Shreiner Metal Violet.

If cracking is a problem, sometimes it’s better to go to the next wider matrix channel for the same rule height and width. In the case of .020” chipboard, I’d go to .075” or 1.9mm scoring matrix (Shreiner Metal Olive). This bends and weakens the coarse fibers without breaking them.

Thanks, Jim! I like your method. Brian

Matrix
Jim’s math is fine but stock weight/density is also a factor.Sometimes its trial and error. My primary business is die cutting and most times involves creasing. I only stock 4 colours of matrix orange, beige, white and mustard (most brands are colour coded the same way) and can crease anything from .005” to .024” stock. To tighten up a crease and allow for thinner stock put some scotch tape on the matrix.
Mike

Thank you all very much!
K.